Method of increasing the yield of sugar from sugarcane

ABSTRACT

The subject matter of this invention is the use of 2,4-dichlorophenoxyethyl 2-[4-(3,5-dichloropyridin-2-yloxy)phenoxy]propanoate as a sugarcane ripener.

This invention relates to a method of increasing the yield of sugarobtained from sugarcane and more particularly relates to a method ofincreasing the recoverable sugar in sugarcane by treating the sugarcaneplant during its maturation with 2,4-dichlorophenoxyethyl2-[4-(3,5-dichloropyridin-2-yloxy)phenoxy]propanoate.

A variety of plant growth regulators, stimulants and promotors have beentried in the past in attempts to increase the yields of cultivatedcrops. It has been found that materials that have an effect on one cropwill not necessarily have an effect or have a different effect on othercrops.

One particular crop which has been given increased attention for thepurpose of increasing yields is sugarcane. Accordingly it is an objectof the present invention to provide new methods and compositions ofincreasing the yield of sugar obtained from sugarcane.

It has now been found that the recovery of sugar from sugarcane can besignificantly increased by the use of certain esters. Consequently ithas now been found that it is possible to increase the recoverable sugarin sugarcane by contacting the sugarcane plant with an effective amountof 2,4-dichlorophenoxyethyl2-[4-(3,5-dichloropyridin-2-yl-oxy)phenoxy]propanoate.

The compound useful in the present method can be readily prepared byknown esterification procedures. Thus the corresponding propionic acidchloride of the structured formula: ##STR1## is reacted with2,4-dichlorophenoxyethanol using standard esterification proceduresi.e., heating in an inert solvent in the presence of an acid scavenger.The following example demonstrates the preparation of the desiredpropanoate ester.

EXAMPLE I Preparation of 2,4-Dichlorophenoxyethyl2-[4-(3,5-dichloropyridin-2-yl-oxy)phenoxy]propanoate

2-[4-(3,5-Dichloropyridin-2-yloxy)phenoxy]propanoic acid (3.7 grams;0.01128 mol) and thionyl chloride (15 ml) were placed into a 50 ml roundbottomed glass reaction flask equipped with stirrer, condenser,thermometer and nitrogen line. This reaction mixture was stirred for11/4 hours at 70° C. cooled and stripped yielding the desired acidchloride.

The 2-[4-(3,5-dichloropyridin-2-yloxy)phenoxy]propanoic acid chloride(3.12 grams; 0.009 mol); triethylamine (5 ml):2,4-dichlorophenoxyethethanol (1.94 grams; 0.0094 mol) and toluene (100ml) were stirred in a glass reaction flask until thin layerchromatographic analysis showed completion of the reaction. This mixturewas transferred to a separatory funnel and washed three times with water(70 ml). The washed material was dried and stripped to a yellow/browngum (4.8 grams) that solidified on standing and was recrystallized froma mixture of methylene chloride and hexane. The first crop (1.5 grams)analyzed by elemental analysis as follows:

    ______________________________________                                                  Theoretical (%)                                                                         Found (%)                                                 ______________________________________                                        C           51.09       51.36                                                 H           3.31        3.28                                                  N           2.71        2.76                                                  Cl          27.42       27.26                                                 ______________________________________                                    

It had a melting point of 100° C. and infrared analysis was consistentwith the desired structure. A second crop (2.0 grams) was also obtained.

The effectiveness of the compounds of this invention for increasing therecoverable sugar from sugarcane was demonstrated in a field test byapplying a solution in acetone diluted for application to sugarcane atthe various indicated application rates. The test compound was appliedat the test rate on the spindle area of each of 20 stalks of sugarcanein a field in Hawaii, using a syringe with a fine needle as theapplicator. A set of 10 of these treated stalks from each group washarvested at 4 and 8 weeks after such treatment. In each harvest a setof 10 untreated stalks also harvested as a control.

The top 14 joints of the treated cane as well as those of the controlswere removed, combined and analyzed for juice purity and pol percentcane, following the "press method" developed and described by T.Tanimoto, Hawaiian Planters Record, 57, 133 (1964). Pol percent cane isa polarimetric determination and equals the percentage of sucrose if thelatter is the only substance in the solution which will rotate the planeof polarized light. The pol percent cane is a standard method ofdetermining the sucrose content of sugarcane.

    ______________________________________                                                    Rate Of                                                                       Application                                                                              Pol %    Juice                                                     (lbs. per acre)                                                                          Cane     Purity                                        ______________________________________                                        Compound of Example 1                                                                       1.0          12.46    82.83                                     Control       0            10.06    76.54                                     ______________________________________                                    

In the use of this compound to increase the recoverable sugar insugarcane, sugarcane is treated at a late stage of development of thesugarcane wherein most of the sugar formation takes place. Thus, undernormal growing conditions and common cultivation practices the activecompound of this invention can be applied to the sugarcane during theperiod of from about 2 to about 10 weeks before harvesting.

The amount of active compound required to effectively increase therecoverable sugar from sugarcane can vary somewhat depending on suchfactors as the time of application, the weather, crop density, method ofapplication and the like. Generally, an amount of at least 0.1 poundsper acre and preferably an amount of from 0.1 pounds per acre to about10 pounds per acre can be used. While an amount greater than thosementioned can be used, they will not result in an advantage that wouldwarrant their expense and are, therefore, not practical.

For practical use in treating sugarcane, the active compounds of thisinvention are generally incorporated into compositions or formulationswhich comprise an inert carrier and an effective amount of the compound.The compositions enable the active compound to be conveniently appliedto the sugarcane at the desired rate. The formulations can be liquidformulations such as emulsifiable concentrates or solutions or solidformulations such as dusts, granules or wettable powders.

The preferred compositions are liquid formulations, particularlysolutions or emulsifiable concentrates. Emulsifiable concentratescomprise the active compound, according to this invention, and as theinert carrier, a solvent and an emulsifier. Such emulsifiableconcentrates can be extended with water and/or oil to any desiredconcentration of active compound for application as sprays to thesugarcane. The emulsifier most commonly used in these concentrates arenonionic or mixtures of nonionic with anionic surface-active agents.With the use of some emulsifier systems an inverted emulsion(water-in-oil) can be prepared.

Typical formulations according to the present invention useful forincreasing the recoverable sugar in sugarcane are illustrated in thefollowing examples wherein the quantities are given in parts by weight.

EXAMPLE 2 Preparation Of An Emulsifiable Concentrate

The following ingredients are blended thoroughly until a homogeneousliquid concentrate is obtained. This concentrate is mixed with water togive an aqueous dispersion containing the desired concentration of theactive ingredients for use as a spray.

    ______________________________________                                        Product of EXAMPLE 1                                                                              25                                                        Sodium lauryl sulfate                                                                              2                                                        Sodium lignin sulfate                                                                              3                                                        Kerosene            70                                                        ______________________________________                                    

EXAMPLE 3 Preparation Of A Wettable Powder

The following components are mixed intimately in conventional mixing orblending equipment and are then ground to a powder having a particlesize of less than about 50 microns. The finished powder is dispersed inwater to give the desired concentration of active compound forapplication to the sugarcane.

    ______________________________________                                        Product of EXAMPLE 1                                                                              50                                                        Fuller's earth      47                                                        Sodium lauryl sulfate                                                                             2.5                                                       Methyl cellulose    0.5                                                       ______________________________________                                    

EXAMPLE 4 Preparation Of A Dust

The following ingredients are mixed thoroughly and are then ground to anaverage particle size of less than about 50 microns to give a dustsuitable for application with conventional dusting equipment.

    ______________________________________                                        Product of EXAMPLE 1                                                                              10                                                        Powdered talc       90                                                        ______________________________________                                    

What is claimed is:
 1. A method for increasing the recoverable sugarcontained in sugarcane which comprises contacting the sugarcane plantwith an effective amount of 2,4-dichlorophenoxyethyl2-[4-(3,5-dichloropyridin-2-yl-oxy)phenoxy]propanoate.
 2. The method ofclaim 1 wherein the sugarcane is contacted with from about 0.1 to about10 pounds per acre of the ester.
 3. The method of claim 1 wherein thesugarcane is contacted with the ester during the period of from about 2to about 10 weeks before harvest.
 4. The method of claim 2 wherein thesugarcane is contacted with the ester during the period of from about 2to about 10 weeks before harvest.
 5. A method of claim 1 in which theester is incorporated in a liquid composition.
 6. A method of claim 5 inwhich the liquid composition is a solution.
 7. A method of claim 5 inwhich the liquid composition is an emulsion.
 8. A method of claim 7 inwhich a nonionic surface-active agent is present.
 9. A method of claim 7in which a mixture of nonionic and anionic surface-active agents arepresent.